CHICAGO (CBS) — In the first possible case of Zika virus in Chicago, health officials are monitoring a patient who recently traveled to a county where the mosquito-borne illness is present.

Doctors at the infectious disease unit at Presence St. Joseph’s Hospital ran blood tests as a precaution, but results won’t be known until next week.

The patient is not in the hospital, but Dr. Mitchell Weinstein told CBS 2 that there is a 50 percent chance the person has the virus.

No details about the patient, or where the person traveled, were made available.

Typically, the virus is spread after people are bitten by infected mosquitoes.

In Dallas, there is one case of Zika transmitted sexually.

In Illinois, two pregnant women are among the three cases of Zika virus in the state.

The third case is an adult male and all have traveled to Latin America, according to the state health department. All three were bitten by infected mosquitoes.